{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:3Y4IZMZFCRUKMIBQMUTO3A2YE6","short_pith_number":"pith:3Y4IZMZF","canonical_record":{"source":{"id":"1803.08039","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-03-19T18:00:08Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"ce12f38fd712b0a4e12fdcc7ab25cc6de1a7855c99a3d9a9a5f468d442775045","abstract_canon_sha256":"41ec9ea83cd03188f4e3087242219f1f1c6575400d40edc240eda85759f65fc9"},"schema_version":"1.0"},"canonical_sha256":"de388cb3251468a620306526ed835827b914e497080c55165309df5e9897122c","source":{"kind":"arxiv","id":"1803.08039","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1803.08039","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"arxiv_version","alias_value":"1803.08039v2","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1803.08039","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"pith_short_12","alias_value":"3Y4IZMZFCRUK","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_16","alias_value":"3Y4IZMZFCRUKMIBQ","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_8","alias_value":"3Y4IZMZF","created_at":"2026-05-18T12:32:05Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:3Y4IZMZFCRUKMIBQMUTO3A2YE6","target":"record","payload":{"canonical_record":{"source":{"id":"1803.08039","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-03-19T18:00:08Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"ce12f38fd712b0a4e12fdcc7ab25cc6de1a7855c99a3d9a9a5f468d442775045","abstract_canon_sha256":"41ec9ea83cd03188f4e3087242219f1f1c6575400d40edc240eda85759f65fc9"},"schema_version":"1.0"},"canonical_sha256":"de388cb3251468a620306526ed835827b914e497080c55165309df5e9897122c","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:13:26.853999Z","signature_b64":"H+aANdwm+H4FvnVsX3WwbrgnsQyOxNCR5kDn9BmY3FkzJWOkTkn5GER0LkYQ0/0qwDpDMiMLK6QKiuIjO7EVAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"de388cb3251468a620306526ed835827b914e497080c55165309df5e9897122c","last_reissued_at":"2026-05-18T00:13:26.853246Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:13:26.853246Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1803.08039","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:13:26Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"EKPt/AVA+iW0o7p0ZnnD23QFp3gNZBJ02bAh2mejRHblEG+yZHodx+7jqt7wXDGW1DoCjQFzqpQjr8qp7F8PBw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-12T19:12:13.921040Z"},"content_sha256":"8475e861318f8d0064b8485546f725b69877eb81e0d1c548a98942ebe321e17b","schema_version":"1.0","event_id":"sha256:8475e861318f8d0064b8485546f725b69877eb81e0d1c548a98942ebe321e17b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:3Y4IZMZFCRUKMIBQMUTO3A2YE6","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A limit on the warm dark matter particle mass from the redshifted 21 cm absorption line","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"Arif Babul (U. Victoria), Evan Scannapieco (ASU), Mohammadtaher Safarzadeh (ASU)","submitted_at":"2018-03-19T18:00:08Z","abstract_excerpt":"The recent EDGES collaboration detection of an absorption signal at a central frequency of $\\nu = 78 \\pm 1$ MHz points to the presence of a significant Lyman-$\\alpha$ background by a redshift of $z=18$. The timing of this signal constrains the dark matter particle mass ($m_\\chi$) in the warm dark matter (WDM) cosmological model. WDM delays the formation of small-scale structures, and therefore a stringent lower limit can be placed on $m_\\chi,$ based on the presence of a sufficiently strong Ly-$\\alpha$ background due to star formation at $z=18$. Our results show that the coupling the spin tempe"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1803.08039","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:13:26Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"QQr3e7+jhg/XtfAHCNLTMF8qWOiHZH2d3NiHj3bQttV8GqofQxPchT3WZWXNgMcWyVuj9OumrAF267IlJzbKBw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-12T19:12:13.921503Z"},"content_sha256":"09dbee24352db229adc5aacd51b51aab1d11f4a363d4c90f1e311ff7c6a132a7","schema_version":"1.0","event_id":"sha256:09dbee24352db229adc5aacd51b51aab1d11f4a363d4c90f1e311ff7c6a132a7"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/bundle.json","state_url":"https://pith.science/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-12T19:12:13Z","links":{"resolver":"https://pith.science/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6","bundle":"https://pith.science/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/bundle.json","state":"https://pith.science/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/state.json","well_known_bundle":"https://pith.science/.well-known/pith/3Y4IZMZFCRUKMIBQMUTO3A2YE6/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:3Y4IZMZFCRUKMIBQMUTO3A2YE6","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"41ec9ea83cd03188f4e3087242219f1f1c6575400d40edc240eda85759f65fc9","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-03-19T18:00:08Z","title_canon_sha256":"ce12f38fd712b0a4e12fdcc7ab25cc6de1a7855c99a3d9a9a5f468d442775045"},"schema_version":"1.0","source":{"id":"1803.08039","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1803.08039","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"arxiv_version","alias_value":"1803.08039v2","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1803.08039","created_at":"2026-05-18T00:13:26Z"},{"alias_kind":"pith_short_12","alias_value":"3Y4IZMZFCRUK","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_16","alias_value":"3Y4IZMZFCRUKMIBQ","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_8","alias_value":"3Y4IZMZF","created_at":"2026-05-18T12:32:05Z"}],"graph_snapshots":[{"event_id":"sha256:09dbee24352db229adc5aacd51b51aab1d11f4a363d4c90f1e311ff7c6a132a7","target":"graph","created_at":"2026-05-18T00:13:26Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"The recent EDGES collaboration detection of an absorption signal at a central frequency of $\\nu = 78 \\pm 1$ MHz points to the presence of a significant Lyman-$\\alpha$ background by a redshift of $z=18$. The timing of this signal constrains the dark matter particle mass ($m_\\chi$) in the warm dark matter (WDM) cosmological model. WDM delays the formation of small-scale structures, and therefore a stringent lower limit can be placed on $m_\\chi,$ based on the presence of a sufficiently strong Ly-$\\alpha$ background due to star formation at $z=18$. Our results show that the coupling the spin tempe","authors_text":"Arif Babul (U. Victoria), Evan Scannapieco (ASU), Mohammadtaher Safarzadeh (ASU)","cross_cats":["astro-ph.GA"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-03-19T18:00:08Z","title":"A limit on the warm dark matter particle mass from the redshifted 21 cm absorption line"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1803.08039","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:8475e861318f8d0064b8485546f725b69877eb81e0d1c548a98942ebe321e17b","target":"record","created_at":"2026-05-18T00:13:26Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"41ec9ea83cd03188f4e3087242219f1f1c6575400d40edc240eda85759f65fc9","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-03-19T18:00:08Z","title_canon_sha256":"ce12f38fd712b0a4e12fdcc7ab25cc6de1a7855c99a3d9a9a5f468d442775045"},"schema_version":"1.0","source":{"id":"1803.08039","kind":"arxiv","version":2}},"canonical_sha256":"de388cb3251468a620306526ed835827b914e497080c55165309df5e9897122c","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"de388cb3251468a620306526ed835827b914e497080c55165309df5e9897122c","first_computed_at":"2026-05-18T00:13:26.853246Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:13:26.853246Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"H+aANdwm+H4FvnVsX3WwbrgnsQyOxNCR5kDn9BmY3FkzJWOkTkn5GER0LkYQ0/0qwDpDMiMLK6QKiuIjO7EVAQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:13:26.853999Z","signed_message":"canonical_sha256_bytes"},"source_id":"1803.08039","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:8475e861318f8d0064b8485546f725b69877eb81e0d1c548a98942ebe321e17b","sha256:09dbee24352db229adc5aacd51b51aab1d11f4a363d4c90f1e311ff7c6a132a7"],"state_sha256":"c63b4a28cb15fd80929cd562f993a6aaa4226c9f36443f2f2ff2bd5393308e51"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"/DEf6iHKOSEEecjOrWMeC8U2XbKSI8lAsap6oOx2xYCFks+5rVtb8r2lxzpbMN2I3LR/t1OLApAKfh8eauKLAg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-12T19:12:13.925393Z","bundle_sha256":"901abd5098f23116ec15d307fa883f1537dfabb40e76f343f63e422df50b0074"}}